Multilayer color photographic film



DENSITY LOG il/T) March 1, 1960 D. W. WOODWARD ETAL MULTILAYER COLOR PHOTOGRAPHIC FILM Filed Dec. 25, 1955 Yellow filler layer Gelatin sublayer. Cellulose acetate 6 Sheets-Sheet J.

Blue-sensi'iive silver halide yellow color former.

1.5 M I I5- 5 4- E q 4 0 6 oo oo' 160 200" "'loo' "soo ido WAVELENGTH IN IILLIHIGRONS WAVELENGTH Ill HILLIHICRONS WAVELENGTH Ill IILLIIIICRONS 1N VENTORS DAVID WlLLCOX WOODWARD. VICTOR FUHUA CHU BY QM 8M 7 ATTORNEY March 1, 1960 D. w. WOODWARD ETAL 2,927,024

MULTILAYER COLOR PHOTOGRAPHIC FILM 6 Sheets-Sheet 2 Filed Dec. 23, 1955 llllllll llll Ill!

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2.0llll 500 600 WAVELENGTH IN NILL INICRONS INVENTORS DAVID WILLCOX WOODWARD VICTOR FU-HUA CHU ATTORNEY Maroh l, 1960 D. w. WOODWARD ET AL 2,927,024

MULTILAYER COLOR PHOTOGRAPHIC FILM Filed Dec. 23, 1955 6 Sheets-Sheet 3 Blue-sensllive silver halide yellow color former.

28 I Yellow filler layer.

73,255 Green-sensillre srlver hollde mogenlo color former.

lnfru red sensmve silver hol|de+yellow 8r mugenlo color formers. 2| Red-sensitive sllver holide cyqn color former.

Gelofin sublayer. Cellulose acetate DENSITY LOG ll/T) 3 E1 9 151 10 2,0 l llIlll| [Ill lllllll|| 2 0 1 1r| |r|| ll llllllNllll WAVELENGTH IN NILLINICRONS WAVELENGTH IN NILLINICRONS INVENTORS DAVID WILLCOX WOODWARD VICTOR FU-HUA CHU ATTORNEY March 1, 1960 D. w. WOODWARD ETAL 2,927,024

MULTILAYER COLOR PHOTOGRAPHIC FILM Filed Dec. 25, 1955 6 Sheets-Sheet 4 Blue sensitive silver halide yellow color former. Yellow filler loyer. Red-sensllive silver holide cyun color former.

Green sensitive silver holide mogenio color former Geloiin subl'oyer Cellulose ocelclle 1 2 e g v LG I 0 E 2 j \j j 2 IZZ%.IZ Elg. 13 2.0 [I llll llll llll llll l||| 2.0 ll|l llll lllllllllllll llll 400 500 600 700 400 500 600 700 WAVELENGTH IN NILLINICRONS WAVELENGTH IN NILLINICRONS INVENTORS DAVID WlLLCOX WOODWARD VICTOR FU-HUA CHU ATTORNEY lnfro-red sensitive sllver holide +yellow 8r mogenio color formers.

DENSITY LOG il/T) March 1, 1960 D. W. WOODWARD ETAL MULTILAYER COLOR PHOTOGRAPHIC FILM Filed D90. 23, 1955 6 Sheets-Sheet 5 Blue-sensitive silver halide +yellow color former Yellow filter layer.

Green-sensitive silver halide +cyan color former Red-sensitive silver halide magenta color former Gelatin sublayer Cellulose acetate \lnfra-red sensitive sllver halide yellow-8| magenta color formers Will/IA WAVELENGTH IN HILLIHICRONS Blue-sensitive silver halide yellow color former. Yellow filter loyer.

Green sensitive silver halide +magenta color former. Separator layer.

Red-sensitive silver halide cyan color former. infra-red sensitive silver halide 4 yellow 8 magenta color formers Gelatin sublayer Cellulose acetate llll ||1| Ill! WAVELENGTH IN NILLIHICRONS INVENTORS DAVID WILLCOX WOODWARD VICTOR FU-HUA CHU ATTORNEY March 1, 1960 D. w. WOODWARD ETA!- 2,927,024

MULTILAYER COLOR PHOTOGRAPHIC FILM 6 Sheets-Sheet 6 Filed Dec. 23, 1955 llll Ill!

2,0llll WAVELENGTH IN HILLIIICRONS 223a 3223 52:26 .523 .SEk 3 2552: +02 3 5 2523-595 u o m 3E5 .630 u oouE x2 .333 25.2: v2-22:

3:: 3 588+ 3:2. 32. 2.228%! vsfi uam 3.53 3-8 32:; +223; 33 3523 820 i a I I r I I I I I I I I I I I I i I a mw WAVELENGTH IN HILLIIIORONS INVENT'ORS DAVID WILLCOX WOODWARD VICTOR FU-HUA CHU ATTORNEY MULTILAYE'R COLOR PHOTOGRAPHIC FILM.

David Willcox Woodward, Little'Silv er, and Victor Fu- Hua Chu, Metu'chen, N.J., assignors to E. I. du Pont 'de Nemours and Company, Wilmington, Del., a corporation of Delaware t Application December 23, 1955, Serial No.555512tl r Claims. (Cl.'. 9 6.-74)

This invention relates to color photography and more 2,927,024 Patented Mar. 1, 1960 'icc other object is to provide such films which can be made in. a simple manner. A further object is to provide such films which can bemade by the use of the standard photo graphic coating equipment. A still furtherobj ect is to provide such films which can be processed in a relatively simple mannerr Yet another object is to provide a process of producing color corrected multicolor images utilizing such films; Still further objects will be apparent from the following description.

In assignees Woodward and Chu application Ser. No. 468,260, fied Nov. 12, 1954, a method is described for integral color correction wherein a conventional mutil'ayer "color film containing color formers in the record emul- 'sion layers is "provided'with auxiliary relatively slower particularly to photographic elements and processes of forming colored images. Still more particularly, it relates to multilayer photographic films which contain lightsensitive silver halide emulsion layers of different sensitivities, each containing a non-diffusing color-former which results in a subtractive dye, and a light-sensitive layer containing a non-diffusing color-former which will yield a masking dye image.

subtractive three color reproduction of thenegative positive type utilizes, in the most common form, three non-diffusing subtractive dyes. .By-subtractive is meant l dyes which have a single absorption band in the radiation region of between about350 millimicronslto 750 millirnicrons. For positive ima-gm that are to be viewed these dyes rnust be complementary to the three primary colors, blue, green and red; these are yellow (minus blue); magenta tminus green) and cyan (minus red). In the case of a negative, duplicating negative or master positive,

morelatiude is possible since the image is to be viewed by another film whose sensitivity, unlike that of the eyes,

can be shifted to longer or shorter wave lengths. Similar- 1y; although a camera negative film will have peak sensitivitiesat about 470ml, 5 60 mg, and 660 m the duplicating negative, master positives andrelease positives may have maximum sensitivities at other wave lengthsborrespondingto the absorption maxima of the dy'eirn'ages they are tobe printed from. However, none'of the available dyes possess ideal spectral absorption characteristics a yqsince they all-absorb to some extent in regions where one or more of the other-dyes alsoyabsorb light. As a result there is contamination of one dye image with another resulting induller less saturated colors. For instance, thecyan (minus red) dye image absorbs to some extent in the, blue and green region and hence controlshot only the red light but to a lesser extent the blue and green emulsion layers sensitive primarily to radiation of wavelength longer than visible light and also containing color formers capable of forming dyes absorbing in the region where the record layer dyes has unwanted absorption and so composed as to form, on supplemental. exposure to infrared light during normal processing, a mask to correct for. the unwanted absorption of one of the record layers.

Anadvantageous modification of the invention of the Woodward and Chu application has. now been discovered whereby two dye images preferably the cyan and magenta which have the highest contamination can be simultaneously corrected by a singlemask layer. This is highly desirable since it provides for more color correction with development forms a latent image in the mask layer.

- fact that correction can be obtained when the exposure record. The other dyes likewise have unwanted absorption. If steps are not taken to correct these deficiencies,

generally unsatisfactory and dull color reproduction results. One of the best methods for correcting the spectral characteristics of the. dyes is by means of masking images in the negative and intermediate films. These masking images in general'are formed in the, color of the unwanted absorption of one of the subtractive dyes but areopposite in-sign to the unwanted absorption, i.e., for correcting a difiiculty in controlling the reproducibility. An object of this invention is to provide new mutilayer photographic negative or intermediate color films which can be readily processed tdmulticolor images with an integral color correction masking image or images. An-

a less expensive film antig jmore important, a thinner film with less internal scattering and hence a sharper image.

from the unexposed silver halides of the record layers depending on the side of the film given the supplemental exposure. I f

A supplemental exposure to infrared radiation during image, which is opposite in sign to the images of the adjacent layers being corrected is believed. to be formed, at least in part, by light either transmitted by or reflected from the unexposed silver halides of the adjacent record w layers. -Whether the exposure is by transmitted or re- ,fle'ctedligh-t depends, naturally, onwhich side the expostu e is made from and the relationship of the individual layers. In any case the developed sliver of the record images absorbs light and prevents exposure of the mask image in such areas. This can be demonstrated bythe is made from either side of a given film or conversely for a given supplemental exposurethe auxiliary layer may be on either side of the emulsion layer being corrected. This can be seen in Example III where the same film is givena supplemental exposure from either side with com parable results. Following is a more detailed description of some of the film elements that form a part of this invention as applied to a threecolor subtractive process The multilayer films of. this invention comprise t a transparent film base which carry three light-sensitive silver halide layers so disposed and sensitized'that. each layer is essentially sensitive to a different regionsof the visible spectrum and each such layer contains a nonof unwanted absorption in other regions of the spectrum,

and a masking silver halide layer sensitive to light of wavelengths above about 700 millimicronsand relatively insensitive to light below 700 millimicrons adjacentto the film support or located between the lower two record emulsions which said masking layer contains non-diffus ing color formers capableof yielding subtractive dyes, of the aforesaid type having principal absorption spectra This- .posure by blue light.

.mask and film base.

in the regions of the unwanted absorption of the subtractive dyes in the two layers closest to said auxiliary dye masking layer.

A multilayer film layer as described above is ex- ;posed to a scene, a multicolor image of the scene or to I partial image of the record imagesfnearest to the; masking layer. The multilayer film elements of the invention of course, will vary in structure because the different record image layers can be disposed in a number of diiferent arrangements. However, the preferred and most desirable forms of this invention arewhen the masking layer is as near the support as possible so that as little interference with or scattering of the original exposure occurs. In this way the sharpest possible record is obtained. For the sake of simplicity and clarity in explaining the invention reference will be made to films having light sensitive silver halide emulsion' 'layer arrangements from the normal exposure surface to the film support. as follows: V

(1) Blue, green and red sensitive and p (21) Blue, red and green sensitive, it beingunderstood that a yellow filter layer or stratum may be disposed in front of the green and red layers to prevent their ex- However, if these lower two layersare rendered less sensitive to blue light than the blue. sensitive layer such a yellow filter layer .is not needed. Also the color correction obtained by this invention can be applied to films having other sensitivity arrangements.

Since the most serious contamination is due to the blue absorption of the cyan and magenta dyes andthe green absorption of the cyan dye, this invention is most 'useful when these two color forming layers are adjacent or separated only by the mask layer so that both can .be corrected by the single mask layer. Because obtaining maximum sharpness requires that the mask layer be as near the support as possible, the following arrange- Jment of color formers are those most useful in the invention.

.A. (1) .Yellow, (2) magenta, (3) orange mask, (4) 'z cyan and film base.

B. (1) Yellow, (2) magenta, (3) cyan, (4) orange C.1Yellow, cyan, orange mask, magenta and film base. D. Yellow, cyan, magenta, orange mask and film base.

1- Although-the color former used in the mask is referred a supplcv and for such a period that there occurs no. significant ex- :Posure of the'other emulsion layer, and continuing the 1 development whereby a masking image cppositedn sign to the record images is formed and corrects the unwanted overall expo s ure from either the fro'ht back side to infrared radiation of wavelength greaterthan 700 m1ll1- microns. When development is completed and the silver and silver salts removed the film contains in addition to the normal three negative dye images, orange positive images corresponding to the negative magenta image and the cyan negative image or vice versa. When the contrast of these correcting images have been made at least equalbut opposite-in sign to that of the'u'nwanted' components .of the magenta and cyan images, the magenta dye imagerro longer will modulate blue light and the cyan; image will no longer modulate blue and green light and hence, are corrected for the unwanted absorption. The gontrast .ofthe orange positive image is determinedby "(Zz'Y'the gamma of'the record images to the suppiement'arymexposing lightat, the time of ex- I posure, (b) the inherent contrast of the auxiliary layer ,the magenta negative image and the blue and green absorptionfof the cyan negative image -,is only'about it) to 30%; asgreatas their blue and greenabsorptions respectively; g

In preparing these films the contrasts of the various component dye images of the. pnmaskedfilm a're' determined. Thus the gamma is measured .at, for instance, 420, .550 and 690 m for the dye imageformed ineach layer of the film. The principal undesired values, that of themagjenta of, 420jand cyan at 420 -and -550', arethe values;to,be corrected. .Next the ga'mmas of the',-magenta and cyan layers to the light to be=used for supplemental exposure Fare determined as they would be during developmentmthat is dye plus silver. Vllith:these*values it is a simple matter to calculate what the inherent gamma of the masking emulsion must bejtotyieldua,thaskwhich j2',2'-diethyl thiatricarboncyanine p-toluene sulfonate, a

to as orange, the'most practical orange dye would absorb more strongly in the region of 400 to 450 m, and 500 to' '0 m than between 450 and 500 me since these values correspond more closely to the sensitivities of multilayer filmon which these corrected films will be printed. A mixture of a yellow color former yielding a dye having an absorption maximum near 445 m and a magenta color'former having an absorption maximum near 533 m is preferred to an orange color former yielding a dye having a single absorption maximum near Inany of the films having the above sensitivities (l density of the cyan are automatically corrected when the film after exposure to a scene or a record of a scene is color developed and duringdevelopment given' an matches-the undesirablegammas'of the cyan and magenta images. Ofcourse in some cases it' may'beidesir'able: to

.use a mask of higher gamma'than would be indicated by the above. .For instance, an improvement ofi'color and a partial correction 'of the unwantedabsorption' of the dyes in the release positive can be obtained in this way by super normally 'very slow to visible light, adequate speeds to' infrared light are readily obtained by dye sensitization. Suitable sensitizing dyes include 1 2, 1 '-.die thyl-3 4-benaothia-4f-carbocyanine iodide, 3,3Fdiethyl-Sjf-dimethyl thiatricarbocyanine iodide, Z-ethyl-3,4-benzothia-2'-benzyl;6'-methyl carbocyanine bromide, and l, i i 2,1grdiethyb6-bron1o-3,4-benzothia-4f carbocyanine ethosulfate. v

Advantages in usingsuch emulsions are'tlia't' beingtrans parent, they do not scatter 'light and so do not adversely affect the resolution orf sharpness of the film.

In the accompanying,drawingswhichform part of this specification: I V I I Figure l is a schematic sectional yiewofthe filrn element of Example I; i

Figmre 2 isa graph containing spectrophotometric'curves of the magenta dye image of difierent' densities'before color correction of the filmelemer'i'tof Figure l;

.Figure 3 is a graph containing "spectrophotometric cnrvesof the magenta dye imageof different densities after color correction of the film element of Figure 1;

Figure 4 is a graph containing spectrophotometric curves of the cyan dye image .of difierent densities before color correctionof the film element'of Figure 1; F gure "5 j a graph "containing spectrophotometric the film cl"; ment of Example II;

Figure" 9 is a graph containing spectrophotometric curves of the magenta dye image of different densities after color correction of the film element of Figure 8;

Figure 10 is a graph containing spectrophotometric curves of the cyan dye image of different densities after color correction of the film element of Figure 8;

Figure 11 is a schematic sectional view of the, film element of Example III; i 1

Figure 12 is a graph containing spectrophotometric curves of the dye image of different densities before color correction of the film element of Figure 11;

Figure 13 is a graph containing spectrophotometric curves of the dye image of different densities after color correction of the film element of Figure 11;

Figure 14 is a schematic sectional View of the film element of Example IV; V

Figure 15 is a graph containing spectrophotometric curves of the dye image of different densities before color correction of the film element of Figure 14;

Figure 16 is a graph containing spectrophotometric curves of. the dye image of different densities after color correction of the film element of Figure 14;

. Figure 17 is a schematic sectional view of the film elementof Example V;

Figure 18 is a graph containing spectrophotometric curves of the dye image of different densities before color correction of the film element of Figure 17;

Figure 19 is a graph containing spectrophotometric curves of the dye image of different densities after color correction of the film element of Figure 17;

Figure 20 is a schematic sectional view of the film element of Example VI.

This application is a continuation-in-part of co-pending application Serial No. 468,260, filed November 12, 1054.

The invention will be further illustrated but is not intended to be limited by the following examples:

Example I A photographic film, as shown in Figure l of the drawing, comprises a transparent cellulose acetate film base 20 bearing in order on one surface a'thin gelatin sublayer 21, a red-sensitive gelatinosilver halide emulsion layer 22 containing the magenta color-former, Z-cyanoacetylphenyl5-benzo-furaldehyde polyvinyl acetal (U.S. Patent 2,680,732), and infrared sensitive Lippmann-type gelatinosilver bromide emulsion layer 23 containing a yell ow colorformer, in-benzoylacetamidobenzaldehyde polyvinyl acetal (US. Patent 2,464,597,) and a magenta color-former, m,-[p-(5-ethylcarbonato-3-methyl 1 pyrazolyl) benzamido] benzaldehyde polyvinyl acetal (Martin US. Patent 2,476,988), a green-sensitive silver halide emulsion layer 24 containing as a cyan color-former, m-(3-rnethyl salicylamido) benzaldehyde polyvinyl acetal (Martin US. Patent 2,489,655), a yellow filter layer 25 composed of yellow colloidal silver dispersed in gelatin as described. in assignees Weaver US. Patent No. 2,806,798, dated Sept. 17, 19 57, and a blue-sensitive silver halide emulsion layer 26 containing the yellow color-former as described above. The film is given an exposure of low intensity from the emulsion side which exposes all layers except the Lippmann emulsion. After being developed for 2 /2 minutes at 70 F. in a solution made by admixing the following components:' i r Grams p-Aminodiethylaniline monohydrochloride 2.5 Sodium sulfite (anhydrous) 10.0 Sodium carbonate m'onohydrate 47.0 Potassium bromide 2.0

Water to make 1.0 liter Adjust pH to 10.5

is given a second overall exposure, thru a 6" x 6" Wratten No. 87 filter from either theemulsion or base side by means of two -volt, 100-watt tungsten filament incandescent lamps maintained ata distance of 4 feet from the film, and development is continued for a total of 6 minutes. After development and following a short rinse, the film is treated successively in the first fixer, bleach and second fixer with a water rinse interspersed. These processing solutions have the following compositions:

First fixer: V i

Sodium hyposulfite grams 240.0 Sodium sulfite (anhydrous) do 15.0 Borax do 18.0 Acetic acid, glacial milliliters 12.0 Potassium alum grams 7 20.0 Water to make 1.0 liter Adjust pH to 4.5 Bleach:

Potassium ferricyanide grams 100.0 Potassium bromide do 15.0 Water to make 1.0 liter Adjust pH to 7.0-8.0 Second fixer: Sodium hyposulfite "grams 200.0 Water to make 1.0 liter Adjust pH to 7.0

The film is finally washed and dried. and 5 are given spectrophotometric curves of the magenta and cyan dye images of different densities respectively before and after color correction by the above-described. It is clearlyshown that the unwanted blue absorption of the magentadye and the unwanted blue'and green absorptions of the cyan dye are completely corrected. In Figures 6 and 7 are also given spectrophotometric curves of the superimposed magenta and cyan dye images of different densities, respectively, before and after color correction by the above-described method. It is evident that the unwanted blue absorption of both magenta and cyan dyes is completely corrected simultaneously.

Example I] A photographic film, as shown in Figure 8 of the drawing, comprises a transparent cellulose acetate film base 20 bearing in order on one surface a thin gelatin sublayer 21, a red-sensitive gelatinosilver halide emulsion layer 27 containing the cyan color-former as described in Example I, an infrared sensitive Lippman-type gelatino-silver bromide emulsion layer 28 containing the yellow and magenta color-formers as described in Example I, a green-sensitive silver halide emulsion layer 29 containing a magenta color-former as described in Example I, a yellow filter layer 30 similar to that described in Example I, and a blue-sensitive emulsion layer 81 containing a yellow color-former as described in Example I. The film is given an exposure of low intensity from the emulsion side, which exposes all layers except the Lippmann emulsion. 1 After being developed for 2 /2 minutes at 70 F. in a color developer as described, in Example I, the film is given a second overall exposure thru a *Wratten" No. 87 filter from either the emulsion or base side, development is continued for a total of .6 minutes and the film is washed, fixed, bleached, fixed, washed and dried as set forth in Example I. In Figures 9 and 10, there are shown spectrophotometric curves In Figures 2, 3, 4

f! of magenta and cyan dye images of difierent densities after correction by the above-described method. Comparing these curves with those of Figures 2 and 4, it becomes evident that the unwanted blue absorption of the magenta dye and the unwanted blue and green absorptions of the cyan dye are well corrected.

Example III i A photographic film, as shown in Figure 11 .of the drawing, comprises a transparent cellulose acetate film base 20 hearing in order on one surface a thin gelatin sublayer 21, a green-sensitive gelatino-silver halide emulsion layer 32 containing the magenta color-former as described in Example I, an infrared sensitive Lippmanntype gelatino-silver bromide emulsion layer 33 contain ing the yellow and magenta colorformers as described in Example I, a red-sensitive silver halide emulsion layer 34 containing a cyan color-former as described in Example I, a yellow filter layer 35 similar to that described in Example I, and a blue-sensitive emulsion layer 36 containing a yellow color-former as described in Examvple I. The film is given an exposure of low intensity from the emulsion side, which exposes all layers except the Lippmann emulsion. After being developed for 2 /2 minutes at 70 F. in a color developer as described in Example I, the film is given a second overall exposure through a Wratten No. 87 filter from the emulsion side, development is continued for a total of 6 minutes and the film is washed, fixed, bleached, fixed, washed and dried as set forth in Example I. In Figures 12 and 13, there are shown spectrophotometric curves of magenta and cyan dye images of different densities after correction by the above-described method. Comparing these curves with those of Figures 2 and 4, it becomes evident that the unwanted blue absorption of magenta dye and the unwanted blue and green absorptions of the cyan dye are well corrected.

Example IV A photographic film, as shown in Figure 14 of the drawing, comprises a transparent cellulose acetate film base 20 hearing in order on one surface a thin gelatin sublayer 21, an infrared sensitive Lippmann-type gelatinosilver bromide emulsion layer 37 containing the yellow and magenta color-formers as described in Example I, a red-sensitive gelatino-silver halide emulsion layer 38 containing the magenta color-former as described in Example I, a green-sensitive silver halide emulsion layer 39 containing a cyan color-former as described in Example I, a yellow filter layer 40 similar to that described in Example I, and a blue-sensitive emulsion layer 41 containing a yellow color-former as described in Example I. The film is given an exposure of low intensity from the emulsion side, which exposes all layers except the Lippmann emulsion. After being developed for 2 minutes at 70 F. in a color developer as described in Example I, the film is given a second overall exposure through a Wratten No. 87 filter from the emulsion side, development is continued for a total of 6 minutes and the film is washed, fixed, bleached, fixed, washed and dried as set forth in Example I. In Figures and 16, there are shown spectrophotometric curves of magenta and cyan dye images of different densities after correction by the above-described method. Comparing these curves with those of Figures 2 and 4, it is evident that the unwanted blue absorption of the magenta dye and the unwanted blue and green absorptions of the cyan dye are well corrected.

Example V V A photographic film, as shown in Figure 17 of the drawing, comprises a transparent cellulose acetate film base bearing in order on one surface a thin gelatin sublayer 21 an infrared sensitive Lippmann-type gelatinosilver bromide emulsion layer 42 containing the yellow and magenta color-formers as described in Example I,

a red-sensitive gelatino-silver halide emulsion layer 43 containing a cyan color-former as described in Example I, a separator layer 44, a green-sensitive silver halide emulsion layer 45 containing a magenta color-former as described in Example I, a yellow filter layer 46 similar to that described in Example I, and a blue-sensitive emulsion layer 47 containing a yellow color-former as de scribed in Example I. The film is given an exposure of low intensity from the emulsion side, which exposes all layers except the Lippmann emulsion. After being developed for 2 minutes at F. in a color developer as described in Example I, the film is given a second overall exposure through a Wratten No. 87 filter from the emulsion side, development is continued for a total of 6 minutes and the film is washed, fixed, bleached, fixed, washed and dried as set forth in Example I. In Figures 18 and 19, there are shown spectrophotometric curves of magenta and cyan dye images of different densities after correction by the above-described method. Comparing these curves with those of Figures 2 and 4, it is evident that the unwanted blue absorption of the magenta dye and the unwanted blue and green absorptions of the cyan dye are adequately corrected.

Example VI A photographic film as shown in Figure 20 of the drawing, comprises a transparent cellulose acetate film base 21, a blue-blind green-sensitive gelatino-silver chloride emulsion layer 48 containing the magenta colorformer as described in Example I, an infrared sensitive Lippmann-type gelatino-silver bromide emulsion layer 49 containing the yellow and magenta color-formers as described in Example I, a blue-blind red-sensitive silver chloride emulsion layer 50 containing. a cyan colorformer as described in Example I, and a blue-sensitive silver bromide emulsion layer 51 containing a yellow color-former as described in Example I. The film is given an exposure of low intensity from the emulsion side, which exposes all layers except the Lippmann emulsion. After being developed for 2 minutes at 70 F. in a color developer as described in Example I, the film is given a second overall exposure thru a Wratten No. 87 filter from either the emulsion or base side, development is continued for a total of 6 minutes and the film is washed, fixed, bleached, fixed, washed and dried as set for in Example I. The unwanted blue absorption of the magenta dye and the unwanted blue and green absorptiIcIms of the cyan dye are well corrected as in Example I In place of the specific immobile or non-diffusing colorformers described in the foregoing examples, which are essentially colorless compounds, various other colorformers having such properties can be substituted in the foregoing examples and analogous procedures with similar results. In these color-formers the color-forming nucleus has as the active color-coupling group a structure which may be represented by the formula:

wherein X is HO- or RHN--, wherein R is hydrogen or an aliphatic group and n is 0 or 1. Compounds of this type include phenolic or naphtholic compounds and aro-- matic primary or secondary amines with hydrogen or replaceable groups, e.g., halogen, carboxyl and sulfonic acid groups para to the hydroxyl and active methylene compounds such as acylacetarylides, cyanoacetyl compounds, pyrazolones and other heterocyclic active methylene-containing compounds. While these are the preferred color-formers, this invention works equally well with couplers and color developers that yield other types of dyes, for instance, the phenazonium and azine dyes as described in the follownig U.S. patents: Coles 2,524,725, Schmidt et a1. 2,536,010 and 2,543,338, Tulagin et al. 2,524,741, 2,525,502, 2,525,503 and 2,591,642, and the dyes described in Jennen U.S. Patent 2,673,801.

Immobilization of these color-formers in the emulsion layers may be accomplished in a number of ways. For instance; high molecular weight substituents including alkyl chainsof 12 ormore carbon atoms and polycyclic groups'may be attached to the color-formers to provide immobility in water-penneable colloid layers, as described in US. Patent 2,179,244 or the color-formers may he immobilized by dispersing ina non-aqueous phaseas shown inU.S. Patent 2,272,191. Onepa'rticularly useful The general structure of these Another advantage of the. invention-is that itprovides new film structures anda' method of processing which can be readily operated to yield multicolorimages of nearly ideal color values.

The invention has the additional advantage in that it provides a practical and effective process for correcting the undesirable absorption of quinoneirnine and ammethine dye images. in the reproduction of original developed multicolor images. We claim: k y

ILA multilayer photographic color film comprising a transparent film base bearing three light-sensitive silver halide emulsion layers and a yellow filter layer so disposed and sensitized that each layer is essentially sensitive to a different primary color region of the visible spectrum taken from the group consisting of blue, green and red regions and contains a nondiifusing essentially colorless, organic color former wherein the color forming nucleus has as the active color coupling group an atomic structure represented by the formula: V

, X .t=a. t=i wherein X is a member of the group consisting of HO,

OH OH where X is a color-former group or nucleus and Y is a H group enhancing hydrophilic character, and the numbers a, b and c are selected to contribute the desired degree H of colloid properties and to provide the required color density after color-coupling development. Such polymers and are described in more detail in US. Patent 2,310,943 3 and in the J. Am. Chem. Soc., 73, 4930 (1951).

These color-formers when used in light-sensitive silver halide layers may constitute the sole binding agents for H the silver halide grains or they can be mixed with polyvinyl alcohol, polyvinyl acetals or partially hydrolyzed polyvinyl esters which are water-soluble or hydrophilic in character and/or other natural or synthetic colloid binding agents for silver halide grains, including gelatin.

Similarly various other primary aromatic amino colordeveloping agents can be used in place of the specific one in the foregoing examples. Suitable additional ones are described in the British Journal of Photography, October 14, 1938, pages 647-648. These color-developing agents can be used in the form of their addition salts, e.g., hydrochlorides and hydrosulfates, which are more solu- =ble and more stable than the free bases.

Various types of hydrophobic films can be used as the base film for the multilayer photographic elements described above. Suitable bases include cellulose deriva tives, e.g., cellulose nitrate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate; superpolymers, e.g., polyvinyl chloride, poly,(vinyl chloride c0 vinyl acetate), and polyethylene "terephthalate. The

known anchoring sublayers which are useful with such bases can be used to anchor the silver halide emulsion layers to the bases.

The supplementary exposure is most simply carried out during color development. However, if desired, the development can be stopped by washingthe film and drying, then giving the supplementary exposure and completing development and processing. V

This invention is, of course, not limited to camera negative films but may be applied equally well to any multilayer color transparency from which copies, prints, duplicates, or other reproductions in color are to be made. Thus the color values in any multilayer color camera negative, master positive, duplicating negative, or other intermediate film may be improved by use of this invention.

where R is an aliphatic group, and n is a number from 0 to 1, said color former being capable of forming, with the oxidation product of a primary aromatic amine develcping agent during the development of exposed silver halide with such an agent, a dye of a subtractive color and taken from the group consisting of quinoneimine and a'zomethine dyes,'and a single masking silver emulsion layer sensitive to light of wavelengths above 700 m and relatively insensitive to light below 700 mp contiguous with the lowermost of the other said three emulsion layers, said masking layer containing at least 1 non-ditfusing color former of the aforesaid type, the subtractive dye image yielded in the masking layer upon development with the same developing agent'being orange and having principal absorption spectra in the regions of the unwanted absorption of the subtractive dyes in the two silver halide emulsion layers nearest said masking layer, said two layers containing cyan and magenta dyes, respectively.

2. A film as set forth in claim 1 wherein the essentially blue-sensitive emulsion layer is outermost and contains a color former capable of yielding a yellow subtractive 3. A film as set forth in claim 1 wherein said masking layercontains non-diffusing colorformers capable of yielding yellow and magenta dyes respectively, to form an orange masking image.

4. A film as set forth in claim 3 wherein the yellow filter layer is below and contiguous with the blue-sensitive ayer.

5. A film as set forth in claim 3 wherein said masking layer is the lowermost layer.

6. A film as set forth in claim 3 wherein the lowermost emulsion layer is red-sensitive.

7. A film as set forth in claim 3 wherein the lowermost emulsion layer is red-sensitive and contains a color former capable of yielding a cyan dye.

8. A film as set forth in claim '3 wherein the lowermost layer is green sensitive.

9. A film as set forth in claim 3 wherein the lowermost layer is green-sensitive and contains a color former capable of yielding a magenta dye. I v A 10. A film as set forth in claim 3 wherein said color formers are polyvinyl acetals having a pluralitypfl'ateral 10 color-forming nuclei as defined in claim 3.

' References Cited in the file of this patent UNITED STATES PATENTS Gasper -QJ. Oct. 29, Mannes et al. Oct. 7, Gasper .May 16, Dearing 'Jan. 29, Jelley et al. July 9, Fierke Oct. 16, Harsh Apt. 8,

, Berger Nov. 9, 

1. A MULTILAYER PHOTOGRAPHIC COLOR FILM COMPRISING A TRANSPARENT FILM BASE BEARING THREE LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYERS AND A YELLOW FILTER LAYER SO DISPOSED AND SENSITIZED THAT EACH LAYER IS ESSENTIALLY SENSITIVE TO A DIFFERENT PRIMARY COLOR REGION OF THE VISIBLE SPECTRUM TAKEN FROM THE GROUP CONSISTING OF BLUE, GREEN AND RED REGIONS AND CONTAINS A NON-DIFFUSING ESSENTIALLY COLORLESS, ORGANIC COLOR FORMER WHEREIN THE COLOR FORMING NUCLEUS HAS AS THE ACTIVE COLOR COUPLING GROUP AN ATOMIC STRUCTURE REPRESENTED BY THE FORMULA: 